Step-ladder.



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FRANK B. UNIJERwoon; 0F" NOBLESVILLE, INDIANA, AssI'eN'oR or ONE-HALF TO FRED E: HEYLMANN, or NOBLESVILLE, INDIANA.

STEP-LADDER.

Specification of Letters Patent.

Patented Aug. 31 1915'.

Appiicaummea June 5, 1915. Serial No. 32,371.

To all whom it may concern 5 Be it known that I, FRANK B. UNDER- wooi), a citizen of the United States, residing at Noblesville, in the county of Hamilton and State of Indiana, have invented certain new and useful Improvements in Step- Ladders, of which the following is a specification.

This invention relates to step-ladders and particularly to the means for uniting the side-rail and prop and for connecting them with the top step of the ladder.

The object of the invention is to provide parallel plates between which the side-rail is rigidly bolted and the prop pivoted; to connect said plates near both ends by integral bridges across the ends of the rail and prop which prevent the spreading of the plates and keeps the two plates level,-that is, keeps the ends of either plate from sagging below the corresponding ends of the other one, and the object is to form said two-plate structure out of a single sheet of metal with an integral step-supporting flange which increases the bearing for the latter and provides a ready means of attachment to the step, and to provide a metal structure which can be used interchangeably with the rail and prop on either side of the ladder in the manufacture of the latter.

I accomplish the above, and other objects which will hereinafter appear, by the mechanism illustrated in the accompanying drawing, in which- Figure 1 is a view of the two plates and tongue in the flat, after being punched but before being formed to shape for use. Fig. 2 is a perspective view of same formed ready for assembly with the side-rail prop and step. Fig. 3 is a side view of the upper end of a ladder embodying my invention. Fig. 4 is a rear elevation showing the same support which. is illustrated in Fig. 3, and Fig. 5 is a perspective view on a smaller scale of an entire step-ladder embodying my invention.

Like characters of reference indicate like parts.

Referring to the drawing, 6 are the siderails which support the steps 7 8 are the props which are braced in the usual manner and 9 is the top step which is supported from the side-rails and props" by the metal connections which constitute the novel fea ture of this invention and comprise a pair of trapezoidal plates 10, 10, each having a pair of upper bolt-holes 11, 11, and lower and closer holes 12, 12, the corresponding holes in the two plates being opposite to each other for the purpose of receiving the same bolt. The upper edges of the two plates near the ends of the latter are connected by integral bridges 13, 13, and projecting outwardly between the two bridges in the same plane therewith and integral with the outside plate 10, is a flange 14, having holes for screws or bolts by which the flange is fastened to the top step. This flange thus increases the bearing surface and support for the top step over that afforded by the area of the bridges. On account of the required spread between the rail and prop on one side with the rail and prop on the other, the plane of the flange 14 and bridges 13, 13, is somewhat oblique to the plates, as shown in Fig. 4. The outline of Fig. 1 shows the form of the blank from which said bridged plates and flange are formed. The latter as shown by the full line is punched out of the middle of the blank, the dotted lines showing the lines on which the flange and two plates are bent.

In assembling, the side-rail 6 is rigidly fastened between a pair of plates by two bolts 15, the upper end of the rail being cut oblique to fit close against the bridge which crosses over it and connects the pair of plates at that end. The prop 8 is secured between the same pair of plates by a single bolt 16 in the lower holes at that end, the upper holes being left vacant, and are only formed for the purpose of rendering the structure interchangeable, or so it can be used on either side of the ladder in its manufacture. The end of the prop is rounded as shown by dotted lines in Fig. 3, and it is continued beyond its pivot-bolt 16 far enough to regulate the spread of the prop away from the side-rail in opening the ladder for use, by contact with the side-rail. The top step is secured to the flange 14 by screws or bolts 17.

The bridges stiffen and strengthen the side plates, keep them from weaving in use and from unevenly sagging, and add very materially to the durability and safety of the step-ladder.

Having thus fully described my invention, what I claim as new and wish to secure by Letters Patent of the United States, is

A metal fastener for step-ladders comprising a pair of parallel plates each having v I an upper pair of holes and a lower pair of closer holes, a bridge integral with both plates connecting the top edges of the latter at each end and an outwardly projected flange formed out of the sheet material between the two bridges, said flange having bolt-holes. I

In witness whereof, I have hereunto set my hand and seal at Indianapolis, Indiana, this 22nd day of May, A. D. one thousand nine hundred and fifteen.

FRANK B. UNDERWOOD. [11. s.'] I Witnessesz J. A. MINTURN, F. WOERNER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, .'D. G.- 

